The highest-speed boards don’t necessarily need the highest-performance materials.
High-tech product developers have been able to take advantage of immense advances in the capabilities of electronic components – mostly among processors, FPGAs and ASSPs, which continue to follow the trend implied by Moore’s Law: to deliver incredible new innovations considered impossible or science-fiction fantasy just a couple of product generations before. As fantastic as this might be, there is a problem: end-users are learning to expect – even demand – the impossible on an ongoing basis.
Each new project is pushing harder at the boundaries than ever before, reaching for out-there performance targets that place pressure on every aspect of the design, from high-performance ICs and software, to finer details like choice of materials. Time, also, is of the essence; the value of that first-to-market advantage has never been more telling, given the current commercial climate.
For projects with no time to lose, the highest-performing, low-loss substrate materials can offer a quick and fuss-free route to ensuring the best possible signal integrity for moving high-speed data. The trade-off comes with the higher BoM cost that applies to every unit subsequently built.
To analogize for a moment: If you need to get somewhere in a hurry, you could choose the most powerful supercar and pay the accompanying hefty price tag. But what if, with a little more driving skill, you could do the journey just as quickly in a basic family hatchback?
Getting back to the engineering world, the challenge for product-development teams can lie in finding the skills to achieve the required signal integrity through design effort, rather than over-specifying the materials through lack of expertise or familiarity with the issues. As I mentioned in my November column, a company may have its own SI experts in-house, or may need to rely on external partners in the supply chain – in particular, PCB manufacturers and materials suppliers. Either way, a large body of information must be brought together before serious decision-making can begin.
Materials suppliers (like Ventec) are ideally positioned to help identify the right grade for the type of product or signal speed range. The choices are not always clearly delineated, however. Our substrate materials, for example, come in speed grades from 1.0 to 6.0, and their properties overlap, so it can be difficult to choose according to speed requirements alone.
Right now, we are seeing a lot of design activity that can take advantage of materials in the low-loss to mid-loss ranges. Typical dielectric constant (Dk) of these materials is about 3.4 to 3.9, and dissipation factor (Df) from 0.005 to 0.015. These correspond with today’s fastest-growing application areas, and include Industry 4.0 equipment, autonomous-driving systems and connected-home electronics. It’s possible to argue that these are essentially high-speed systems that require high-end materials. But with a little design expertise, taking the time to engineer-in lower performance materials can reap valuable rewards over the lifetime of the product. The difference could be as much as $10 per board in some cases. For a high-volume product like a consumer or automotive controller, the total financial savings could easily be millions. It is important to understand that working with low-loss materials can have this kind of impact on the BoM cost. Engineers can easily overlook this and become drawn into chasing a few cents here and there on ICs, or passives or connectors, when a better-informed approach to SI can trim several dollars from each unit.
The message here is SI is a specialized field. Are OEMs lucky enough to have the necessary expertise in-house to fine-tune that aspect of the design for optimum performance? In practice, experience from a wide variety of situations is needed to be able to balance performance across all relevant parameters and reach a best-fit at the right price.
At Ventec, we work with organizations throughout the SI value chain, from chipmakers to PCB manufacturers, independent design houses and product OEMs. Because of this, our learning curve is always a very steep ramp, and we are positioned to connect the information and experiences from all these sources to help customers create high-performing solutions that are also cost-effective. As I said to my son many years ago, if 10 people speak to you for 10 minutes, then you gain 100 minutes’ worth of knowledge, whereas each of them still only has one-tenth of that.
When OEMs invite us to help solve their signal-integrity challenges, we usually work with their engineering teams, and other partners such as connector suppliers, to develop test mechanisms and test boards. The measurements often show that the desired performance could be delivered by making various improvements to the design, resulting in significant savings in the bill of materials, and ultimately a more competitive price for end-users, the trade-off being some extra time needs to be spent to develop those design improvements fully.
The key is to be able to build this extra design effort into the project, while still hitting that all-important market window. And this is where consulting services can add value to a customer’s project. You can be on time and overpriced, or competitively priced and late to market, or you can invest in the necessary knowledge – either on a customer-support basis or a more formal technical partnership – to get to market within your window and at a keen price that gives a competitive advantage.
Martin Cotton is director OEM technology at Ventec International Group (ventec-group.com); This email address is being protected from spambots. You need JavaScript enabled to view it..
